A whole discipline of research has evolved around the search for non-conventional sources of hydrocarbons, gas hydrates being a forerunner. Gas hydrates (crystalline form of methane and water), an important future energy resource, have been delineated along the Indian offshore region using seismic images as well as heat flow studies. CSIR-NGRI has conducted several pioneering investigations based on seismic attenuation, attributes, travel time tomography, AVO modeling, full-waveform inversion, rock physics modeling for the identification and quantitative assessment of gas hydrates along the Indian continental margin. Gas hydrates were detected by identifying bottom simulating reflector (BSR) (marker for gas-hydrates) in the Krishna-Godavari, Mahanadi and Andaman regions using the multichannel marine seismic (MCS) data. Thin hydrate-bearing sediments in Goa and Saurashtra offshore were detected by employing the highly non-linear full-waveform inversion to the MCS data. NGRI participated actively in the preparation of gas hydrate stability thickness map along the Indian shelf. An acoustic full waveform inversion (FWI) in frequency domain with a fixed background density has resolved the fine scale velocity structure of gas hydrate bearing sediments in the Krishna Godavari basin of eastern Indian margin, where multichannel seismic data were acquired in 2010 using 360 channels with 12.5m receiver interval, 25m shot spacing and 100m near offset. A methodology of porosity estimation from inversion of post-stack seismic data by utilizing an estimated porosity wavelet, low frequency model and model based inversion is implemented on two types of 2D post-stack seismic dataset; (a) deep water Mahanadi (MN) offshore containing gas hydrate sediments and (b) clay rich, shaly sediments in KG shallow offshore. The predicted porosities of the different formations were found to be within realistic range of values.
A significant technique development has been accomplished by utilizing artificial neural network to didtinguish geological features like faults, mud diapirs, mud volcanoes, salt bodies, slum deposits, debris from gas clouds/chimneys based on seismic attributes. This study acts as an add-on-tool for understanding the petroleum system and provides preventive clues for mitigating hazards in future exploitation program for the petroleum industry and the technique has the potential to be extended in characterizing reservoir properties such as the porosity, permeability, saturation etc.
|Dr. Kalachand Sain||Chief Scientist|
|Dr. Prasad P. S. R||Senior Principal Scientist|
|Dr. Satya Vani N||Senior Scientist|
|Dr. Maheswar Ojha||Scientist|
|Mr. Prasad A. S. S. S R. S||Principal Technical Officer|
|Mrs. Prasanthi A||Senior Technical Officer (2)|
|Mr. Vivekanand Pandey||Senior Technical Officer (1)|
|Mr. Mohd. Rafique Shamshoddin||Technical Assistant|
|Mr. Satendra Singh||Technical Assistant|
|Mr. Anil Kumar G||Senior Technician (2)|
Page Last Updated On : 29-11-2018